| 摘要 |
<p>A torsion spring return system for a valve closure member, preferably for downhole use in an SSV, is described. The closure member or flapper uses torsion springs which can be wrapped circumferentially within the body of the downhole tool, generally following the periphery of the flapper. Downward rotation of the flapper stresses the torsion springs so that subsequently, when a flow tube or other device holding the flapper in one position is released, the torsion springs return the flapper to its seat. The connection between the torsion springs and the pin supporting the flapper is either a universal joint or involves an alignment rod running through the torsion spring, as well as other mechanisms which facilitate stress relief in the connection between the torsion spring and pivot pin.</p> |
